1. Field of the Invention
The invention relates to a method for controlling the transmission of DC current between at least one rectifier station and several inverter stations and, in particular, a method in which the reference inputs for the controllers of the rectifier and the inverter stations are formed as a function of the current and the voltage in the DC network.
2. Description of the Prior Art
Such a method is disclosed in German Offenlegungsschrift No. 1,588,750. In the disclosed method, a reference input is formed as a function of the voltage in the DC network, and the control of the individual inverter stations takes place in accordance with their natural characteristics. With such a control of the individual stations, there is mutual interaction between them. Thus, for example, when the power consumption is increased in one inverter station the other inverter stations must reduce their power consumption accordingly, if the rectifier stations have reached their power limit. As a result, when using this control method, a given amount of power cannot be reliably made available to an individual or several inverter stations. The latter shortcoming of the aforesaid prior art method can be overcome by providing a centrally arranged balancing device for the reference input, but such an arrangement requires the employment of a highly complex transmission means for transmitting the corresponding measurement values of the individual rectifier-inverter stations to the balancing device.
It is, therefore, an object of the present invention to provide a method for transmitting DC current between at least one rectifier and several inverter stations in which power consumption of the individual inverter stations can be controlled up to a given, predetermined value without the need of a central balancing device and without mutual interaction.